Unidirectional breather



May 7, 1935.

L. C. NICHOLS UNIDIRECTIONAL BREATHER Filed May 14, 1931 Patented May 7, 1935 PATENT OFFICE -UNIDIBECTIONAL BREATHE! I Louis C. Nichols, Wauwatosa, Wls., assignor to Allis-Chalmers Manufacturing Company, Milwaukee, Wls., a corporation of Delaware mamas May 14, 1mm No. 537,303

15 Claims. (01. sat-s) This invention relates to breathers for transformers, oil circuit breakers, and the like.

Electrical apparatus of this type usually have either a main or an auxiliary tank which is par- 5 tially illled with oil, leaving an air space in the tankabovethe oil. Theairinthisspaceabove the oil is ordinarily in communication with the outside air by means of an opening in the top of the tank commonly called a breather because it permits the tank to breathe air in or out as the oil. contracts and expands due to temperature changes. Since the apparatus usually breathes in and out through. the same opening there is practically no circulation of air within the tank. The air in the tank above the oil is heated by the warm oil and therefore readily absorbs moisture from the air coming in through the breather and also from the oil, and since there is substantially no circulation of this air, the moisture content increases. When the conditions are such that the metal top of the tank cools the moisture laden air in the space above the oil to a temperature below the dew-point of the air, moisture will condense on the inner surfaces of the tank cover'or top. This moisture accumulates and causes rusting, and dripping of water and rust into the oil and onto the elmtrical parts below with the resulting danger of the insulation breaking down and causing destructive arcing. j I

An object of this invention is to minimize the danger of insulation breakdown and rusting or! metal parts in transformers, oil circuit breakers, and the like due to the moisture in the air therein;

Another object of this invention is to prevent the condensation of the moisture in the air in the space above the insulating liquid in transformers, oil circuit breakers, and the like.

Another object of this invention is to provide a container partially filled with oil or similar liquid that is subjected to temperature changes with a "breather" means which willprevent condensation of moisture in the space above the liquid.

Another object of this invention is to attain the above objectsby utilising heat from the insulatim liquid to induce. uni-directional flow of fresh air through the space above the level of the insulating liquid. T

A further object is to provide a device which can be cheaply manufactured and readily inof which will be apparent from the description and drawing herein, and will be more particularly pointed out in the claims.

Various illustrative examples of the application of this invention are shown in the accompanying drawing in which: I

Fig. l is a view partly in section of a transformer having an expansion tank embodying the invention. v

1 13.215 a sectional view of a conventional 10 single tank transformer embodying the invention.

Fix. 3 is a sectional view of a conventional transformer embodying a modified form of the invention.

F18. 4 is sectional view along the line IV--IV of 15 Fig. 3.

Fig. 5 is partial section view of an oil circuit breaker embodying the invention. a

Fig. 6 is a side view of a transformer similar to Fig. 1 showing the expansion tank in section and including the invention.

Referring now in more detail to the drawing, in Fig. l, E designates the main tank of a transformer which has a cover it. The expansion or conservator tank H is supported from the main g5 tank by means of brackets i2-.-i3. An oil conduit it connects the. expansion tank H with the main tank 8 forms a conduit'for the passage of oil It to and from these tanks. A gauge i8 is provided indicate the height of the oil in the tank so ii. A ventilating intake. conduit l'l extends from outside the expansion tank H upwardly through the bottom of tank ii at one end thereof and through the oil II to a point near the top of the tank. The air conduit i1 is attached to the tank Ii by welding or by any suitable pipe connection. A chamber ll containing a deoxidizing agent may be attached to the intake conduit H. A screen II is attached to the inlet end of pipe I I and serves to preventthe admission of foreign mat 4o ter into the intake pipe. An outlet conduit i0 is connected to the top of the tank ll near the end opposite to the intake and serves as a conduit for carrying air from inside the tank H to the outside air. The outlet conduit is unobstructed I by check valves or the like but it does preferablycontain a screen as does the inlet conduit to keep out foreign matter. Obviously this outlet 2| may take the form ofany of the known "weathers", it being understood, however, that in apparatus constructed in accordance with this invention, the circulation of air through the breather will be uni-directional. instead of in and out as heretoore.

Theoperation ,of Fig. 1 is asfollowsz-When ll placement of the air above oil I5 and consequent sweeping out of air throughout the space above the oil and out the outlet conduit 20. The air coming into the tank II being warmer than the outside air will readily absorb moisture from the walls of tank I I and from the oil I5 and will discharge this moisture laden air through conduit 20. It will thus be seen that the moisture content of the oil I5 will be reduced and that rusting of the metal top of tank I5 will be prevented; also the dielectric strength of good oil will be maintained at a high value and the dielectric strength of oil containing moisture will be gradualLv improved. In some installations it may be desirable to remove the oxygen from the air entering theinlet of pipe I! to prevent sludging of the oil within the tank, and this is accomplished by the action of suitable chemicals within container it through which the intake air passes. If this action is not desired, chamber I8 may be removed and the screen I 9 attached directly to conduit II. The tank II has been shown and described as an expansion tank for a transformer, however, the invention may be applied in a similar manner in conjunction with any container for oil or similar material that is subjected to changes in temperature, for example, an oil storage tank subjected to atmospheric temperature changes.

In Fig. 2 a transformer of the single tank type is shown. The tank or casing 2I is provided with a top member 23. The core and windings are designated generally by 22. The usual conductors are led through bushings 24 and 25 to the transformer windings. A conduit 26 extends through the tank 2i near the bottom thereof, vertically upward within the transformer to a point above the level of oil I5 and constitutes an air inlet conduit. This conduit 26 is attached at its lower end to the tank 2| either by welding or by any suitable connecting means, and at its upper end by a guide member or bracket 28 which is welded or otherwise fastened to the tank H. The conduit 26 is shown as bent at its lower end, but it will be understood that suitable pipe fittings can in Fig. 1) may be interposed in the inlet conduit if so desired. An outlet conduit 20 is attached to the upper part of top 23 and serves to exhaust the air drawn in by the action of conduit 28. In some instances, sufllcient draft through conduit 28 may be secured by placing the inlet connections at a higher point in casing M or it may be extended through the bottom of the tank as shown in Fig. 5. The operation of this figure is the same as that described in connection with'Fig. 1.

In Figs. 3 and 4 a transformer of conventional type having corrugated side walls 3| is shown. To the upper cylindrical portion 22 of this-transformer is attached by welding or other connecting means an intake conduit 34 which extends vertically downward, between adjacent corrugations 33. A detachable element 31 carrying screen 22 is provided in the intake of the inlet end of conduit 34, and the upper end of this conduit is in communication with the inside of the transformer at a point above the level of oil IS. An outlet conduit 2B is provided in the cover member 38 of the transformer. The radiation of heat from corrugations 3| is usually sufhcient to induce circulation of air through conduit 34 through the space above oil I5 and out outlet 20, but should it be desired to increase this circulation, heat conductive material 36, such as copper-wool, may be packed around inlet conduit 24 between corrugations 3| and retained in place if necessary by a sheet metal member 35 welded or otherwise attached to the corrugations 3|. The lower end of conduit 24 is attached to the side walls 3| of the casing by means of element 35 or by means of a guide bracket such as shown at 28 in Fig. 2.

In Fig. 5 the invention is shown as applied to a conventional type oil circuit breaker having casing 40, guard member 4 I, movable switch blade 42 and stationary switch clips 43 supported by insulator 44. The switch 42 is operated by operating rod 45 through mechanism (not shown) in the switch housing 45. An intake conduit 41 extends vertically through the bottom of casing I4 through oil I5 to the air space above the oil I5 and is attached to the casing at the bottom by welding or other connecting means and near the top by the supporting member or bracket 49 which is welded or otherwise fastened to tank 40. A screen 48 covers the inlet opening of conduit 41 and serves to keep out foreign matter. The air which is drawn into the space above the oil circulates through openings 50 around the operating rod 45 into the chamber. 46 housing the switch mechanism and finally out the outlet conduit BI. It is evident that the successive operations of the oil circuit breaker will heat up the oil and cause the ventilating air to circulate in the manner described in connection with Fig. 1.

Fig. 6 illustrates an application of the invention 0 to a transformer having an expansion tank of the type shown in Patent No. 1,793,820, granted to L. C. Nichols on February 24, 1931. The main tank 8 supports the expansion tank II by means of the oil conduit 52 which is welded or otherwise fastened to tanks I0 and II. The intake and outlet conduits I1 and 20 are shown as provided with screens I9 and I8 respectively. The oil conduit 52 extends through the expansion tank and is covered by ahinged relief valve 53 which upon occurrence of abnormally high pressures opens to relieve the internal pressure. The embodiment of the invention shown in this figure operates the same as described in connection with Fig. 1.

For the purposes of explanation of the specific embodiments shown herein, reference has been made to the outlet conduit member as being in the top of the casing. The term top as used in this connection is intended to include any wall portion of the casing above the level of the liquid contained in the vessel. Also the medium above the level of the oil and in the inlet and outlet members has been referred to as air, however, it is readily apparent that the invention is applicable in a like manner with any gaseous medium similarly used.

It is thus evident that the above devices provide means for utilizing the heat from the insulating oil of transformers and oil circuit breake s to cause a uni-directional circulation of air or .znert gas through the space above the oil i, and show that this invention may be practiced by using an air intake conduit mounted either inside or outside the apparatus. It is to be understood that the devices above described are merely illustrative of the invention for it will be apparent that various changes in the arrangement and proportion of parts may be'made within the scope of the invention as defined in, the appended claims.

It is claimed anddesired to secure by Let Patent:

i. In combination, a casing for electrical apparatus, said casing containing a quantity of liquid at a higher temperature than the atmosphere and having an air space above the level of said liquid, said casing having an .air vent above the level of said liquid. an air inlet conduit having an air inlet opening located below the level of said liquid and in communication with atmosphere, said inlet conduit extending parallel to said casing for substantially the same distahce as the depth of the liquid within said casing, and means for securing said inlet conduit to said casing in heat conductive relation to said hot liquid so that heated air within said conduit induces a uni-directional circulation of heated air through said air space and out through said vent whereby moisture within said air space is removed by said heated air.

2. In combination, a fluid container, a quantity of liquid at a higher temperature than the atmosphere partially filling said container so as to leave an air space above the level of said liquid, an air outlet ailording unrestricted cgnmunication between said air space andatmosphere, an air inlet conduit having airinlet opening located below the level said liquid and aflording unrestricted communication between said air space and atmosphere, and means for holding said inlet conduit to said casing in heat conductive relation to said liquid so that moisture within said air space is carried out through said outlet by a uni-directional movement of heated air through said air space.

3. The combination with a main casing for electrical apparatus, of an auxiliary casing, insulating liquid filling said casing and partially filling said auxiliary casing, a conduit between said main casing and said auxiliary casing providing a passageway for said liquid, an air outlet conduit in said auxiliary casing, and an air inlet conduit in said auxiliary casing extending from a point about the level of said liquid spaced from said air outlet through said liquid and through said auxiliary casing to the outside air near the bottom of said auxiliary casing.

4. In combination, a casing for electrical apparatuses quantity of insulating liquid partially filling said casing, an air outlet conduit in the top of said casing, an air intake conduit extending from above the level of said liquidthrough said liquid and through said casing to the outside air near the bottom of said casing.

5. In combination, a casing for electrical apparatus, said casing having corrugations in the sides thereof, a quantity of insulating liquid partially filling-said casing, an air conduit extending upward between adjacent corrugations of said casing and into said casing above the level of said liquid, means for transferring heat from said liquid to said conduit, and a second conduit mouted in the top of said casing above the level of said quid.

6. In combination, a casing for electrical ap- 'paratus, a quantity of liquid partially filling said conductive relation to said liquid and providing an unrestricted path for the flow of heated air into said air space.

8. In combination, a casing, a quantity of liquid partially filling said casing so as to leave an air space in said casing above said'liquid, said liquid normally having a temperature higher than the atmosphere adjacent said tank, an outlet vent providing unrestricted communication between said air space and atmosphere, and an unrestricted air inlet ccnduit arranged in intimate heat transferring relation to said liquid and providing a permanently free passageway from atmosphere to said air space through said inlet conduit, whereWh'eated air flowing from within said air space.

9. In a casing having a quantity of liquid therein and an air space above said liquid, an outlet vent mounted on said casing so as to provide a continuously unrestricted passage for the flow of air from said space'to atmosphere, an inlet conduit so mounted on said casing in heat conductive relation to said liquid as to provide a continuously unrestricted path for the flow of air from atmosphere into said space at a point removed from said outlet vent so that the air in said inlet conduit is warmed by said liquid and is thereby caused to absorb and carry moisture from said air space through said outlet vent to atmosphere.

10. In a tank having a quantity of liquid therein and an air space above said liquid, the combination of an outlet member so mounted on said tank as to provide a path for the flow of air from said air space to atmosphere, means providing a path for the uni-directional and continual ,tlow

said inletcorlduit is capable of absorbing moisture of air from atmosphere into said air space ata temperature higher than the temperature of the atmosphere comprising an inlet member mounted on said tank in heat conductive relation to said liquid.

11. In combination, a tank for oil immersed electrical apparatus, a body of oil in said tank for dissipating the heat from said electrical apparatus to said tank, said tank having an air space therein above the level of said oil, means providing a permanently free path for the flow of air from said air space to atmosphere, means for Producing a uni-directional flow of, heated air through said air space comprising an inlet conduit arranged in'intimate heat transferring relation tosaidbodyofoil. I

12. In combination, a tank for oil immersed electrical apparatus, a body of oil in said tank for dissipating the heat from said electrical apparatus to said tank, said tank having an air space therein above the level of said 011, an outlet memberproviding a permanently free path for the flow of air from said air space to atmosphere,

an inlet conduit arranged so that substantially the whole length thereof is in intimate heat transferring relation to said body of oil and providing a permanently free passageway for the flow of air from atmosphere to said air space at a point thereof remote from said outlet member.

13. In combination, a casing, a quantity of in sulating liquid partially filling said casing, an

5; outlet conduit extending through said casing 10 ing.

14. In combination, a casing, a quantity of insulating liquid partially filling said casing, an outlet conduit in said casing above the level of mid liquid, an inlet conduit extending from a pdnt 15 above the level of said liquid h ugh said casing to a point external thereof near the bottom of said casing, and means for supporting said inlet conduit in heat transferring relation to said liquid.

15. In combination, a casing, a quantity of liquid partially filling said casing, said casing having a space above the level of said liquid, an outlet member providing a permanently free path from said space to the outside of said casing, an inlet conduit arranged so that substantially the whole length thereof is in intimate heat transferring relation to said liquid and providing a permanently free passageway from a point external to said casing to said space at a point thereof spaced from said outlet member.

LOUIS C. NICHOLS. a 

